Sheet manufacturing apparatus and sheet manufacturing method

ABSTRACT

A recycled sheet in which fibers are bonded via an additive agent includes a history including information that is related to characteristics.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/215,866 filed in Jul. 21, 2016, a continuation applicationof U.S. patent application Ser. No. 14/658,512, filed on Mar. 16, 2015.This application claims priority to Japanese Patent Application No.2014-061554 filed on Mar. 25, 2014. The entire disclosures of U.S.patent application Ser. Nos. 14/658,512 and 15/215,866, and JapanesePatent Application No. 2014-061554 are expressly incorporated byreference herein.

BACKGROUND

1. Technical Field

The present invention relates to a sheet manufacturing apparatus and asheet manufacturing method.

2. Related Art

In the related art, in a sheet manufacturing apparatus, a so-called wettype method of feeding a raw material including fibers into water,disintegrating the material mainly by a mechanical operation, andrepulping, is employed. A sheet which is manufactured by the wet typesheet manufacturing method, has a structure in which cellulose fiberswhich are derived from wood or the like are intertwined with each other,and are partially bonded by a bonding force, such as hydrogen bonding.

In addition, as a manufacturing method of a waste paper sheet or a fiberboard which uses paper-manufacturing waste, such as pulp waste,screening waste, or cleaner waste, which is generated when waste papersheets or the like are disintegrated, as a raw material (pulp rawmaterial), for example, JP-A-10-121400 discloses a method of forminginto a predetermined shape by heating and pressing a raw materialmixture which is made up to contain 2% by weight to 20% by weight ofplastic on a dry weight basis and 10% by weight to 30% by weight of adry type defibrated raw material (fibrous material), which is made bymaking a paper sheet or a wood material have a fibrous form by a drymethod, on a dry weight basis, by using at least one of types of papersheets, such as waste paper sheets and the paper-manufacturing waste asa main component.

According to this method, when the raw material of the fiber board has aplastic content at a proportion in which a proportion of plastic in theraw material mixture exceeds a predetermined range, the proportion ofplastic in the raw material mixture is brought within the predeterminedrange by removing a part of plastic in the raw material of the fiberboard. In addition, when the raw material of the fiber board has aplastic content at a proportion in which the proportion of plastic inthe raw material mixture is below the predetermined range, additionalplastic is added so that the proportion of plastic in the raw materialmixture is within the predetermined range.

However, in JP-A-10-121400, there is no specific description allowingunderstanding of how much plastic is contained in the raw material ofthe fiber board. For this reason, even those skilled in the art cannotrealize adjustment of the proportion of plastic to a predeterminedproportion. For this reason, the proportion of plastic in this method isinevitably in a wide range of 2% by weight to 20% by weight, and whenthe proportion of plastic is in such a wide range, strength of themanufactured sheet is not constant, and for example, there is apossibility that a sheet which has extremely insufficient strength maybe manufactured.

In addition, a manufacturing method of a desired sheet by recyclingwaste paper sheets plural times has not been suggested until now.

SUMMARY

According to one aspect of the present invention, a recycled sheet inwhich fibers are bonded via an additive agent includes a historyincluding information that is related to characteristics.

According to the aspect of the present invention, the history includesthe information that is related to at least one of a content of theadditive agent, a type of the additive agent, a length of the fibers, amaterial of the fibers, information on the number of times of beingrecycled, information corresponding to a type of the recycled sheet, andinformation on a sheet manufacturing apparatus that is used inrecycling.

According to the aspect of the present invention, the history isrepresented by at least one of a character, a symbol, a hole, anunevenness, and a bar code.

According to the aspect of the present invention, the additive agent isa complex body in which resin and coagulation inhibitor are integrated.

According to the aspect of the present invention, the additive agent isa complex body in which resin and coloring material are integrated.

According to the aspect of the present invention, the additive agent isa complex body in which resin, coagulation inhibitor, and coloringmaterial are integrated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic view illustrating a sheet manufacturing apparatusaccording to an embodiment.

FIG. 2 is a schematic view illustrating the sheet manufacturingapparatus according to the embodiment in which a modification example ofa mixing unit is employed.

FIG. 3 is a functional block diagram illustrating the sheetmanufacturing apparatus according to the embodiment.

FIG. 4 is a table illustrating an additive agent or the like and aregenerated material in each Example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, an appropriate embodiment of the invention will bedescribed in detail with reference to the drawings. In addition, theembodiment described below does not unduly limit the contents of theinvention described in a range of aspects. In addition, the entireconfiguration described below is not necessarily essential forconfiguration requirements of the embodiment.

A sheet manufacturing apparatus according to the embodiment includes: adefibrating unit which defibrates a raw material including at leastfibers; an addition unit which adds an additive agent to a defibratedmaterial which is defibrated in the defibrating unit; and a sheetforming unit which forms a sheet by bonding a plurality of fibers toeach other via the additive agent. According to a history of the rawmaterial, an amount of the additive agent which is fed by the additionunit of the additive agent with respect to the raw material varies.

In addition, in the specification, in the sheet manufacturing apparatus,with respect to a flow (including a schematic flow) of a material (rawmaterial 1, defibrated material, web W, sheet S, or the like) of thesheet to be manufactured, expressions, such as “upstream” or“downstream”, are used. In addition, an expression “upstream side(downstream side)” is used when a position of constituent elements isrelatively specified. For example, “A is on the upstream side(downstream side) of B” means that a position of A is upstream(downstream) with respect to a position of B with reference to the flowdirection of the material of the sheet S.

In addition, in the specification, a dry method means a method in theatmosphere (in the air) not a method in liquid. In a category of the drymethod, a dry state, and a state where liquid (water or the like) whichexists as impurities or liquid (water or the like) which is addedintentionally, vapor, mist, or the like, exists, are included. Inaddition, between the dry method and a wet method which is performed bypulp-molding or the like, it should be noted that amounts of water usedwith respect to the entire apparatus or amounts of paper sheets to bemanufactured are completely different in each method. In other words, inthe dry method, an amount of water when the water exists in the systemis extremely small compared to that in the wet method.

1. Sheet Manufacturing Apparatus

A sheet manufacturing apparatus 120 according to the embodiment includesa defibrating unit 20 which defibrates a raw material 1 which includesat least fibers, an addition unit 32 which adds an additive agent to adefibrated material which is defibrated in the defibrating unit 20, anda sheet forming unit 40 which forms a sheet S by bonding a plurality offibers to each other via the additive agent. FIG. 1 is a schematic viewillustrating the sheet manufacturing apparatus 120 according to theembodiment. Hereinafter, the sheet manufacturing apparatus 120 of theembodiment will be described mainly focusing on the defibrating unit 20and the addition unit 32.

1.1. Defibrating Unit

The defibrating unit 20 defibrates the raw material 1 which includes atleast fibers. By defibrating the raw material 1, the defibrating unit 20generates defibrated material which is disentangled in a fibrous form.In addition, when the raw material 1 is printed waste paper sheets orthe like, the defibrating unit 20 has a function of separatingmaterials, such as resin grains, ink, toner, or a blur-preventing agent,which are adhered to the raw material, from the fibers.

Here, “defibrate” means untangling the fibers in the raw material whichis made by bonding a plurality of fibers one by one. The material whichpasses through the defibrating unit 20 is called “defibrated material”.There is a case where examples of the “defibrated material” includematerials, such as resin (resin for bonding a plurality of fibers toeach other) grains which are separated from the fibers when untanglingthe fibers, ink, toner, or blur-preventing agent, in addition to theuntangled fibers. A shape of the disentangled defibrated material is astring shape or a ribbon shape. The disentangled defibrated material mayexist in a state of not being intertwined with other disentangled fibers(a state of being independent), or may exist in a state of beingintertwined with other disentangled defibrated material in a massedshape (a state where a so-called “lump” is formed).

The defibrating unit 20 is provided on a further upstream side from amixing unit 30 which will be described later. Other configurationelements may be provided between the defibrating unit 20 and the mixingunit 30. In addition, other configuration elements may also be providedon an upstream side of the defibrating unit 20.

The defibrating unit 20 is any arbitrary unit as long as the unit has afunction of performing the defibration processing of the raw material 1.The defibrating unit 20 performs defibration by the dry method in theatmosphere (in the air). In the example in the drawing, the raw material1 which is introduced from an introduction port 21 is defibrated by thedefibrating unit 20, becomes the defibrated material (fibers), and isdischarged from a discharge port 22. The defibrated material which isdischarged from the discharge port 22 is supplied to the mixing unit 30(in the example in the drawing, a tube 86), via a tube 82, a classifyingunit 63, and a screening unit 35.

The configuration of the defibrating unit 20 is not particularlylimited, and examples of the configuration can include a configurationwhich has a rotary unit (rotor) and a stationary unit that covers therotary unit and forms a void (gap) between the rotary unit and thestationary unit. When the defibrating unit 20 is configured in thismanner, as the raw material 1 is introduced to the gap in a state wherethe rotary unit rotates, the defibration processing is performed. Inaddition, in this case, the number of rotation of the rotary unit, ashape of the rotary unit, a shape of the stationary unit, or the like,can be appropriately designed by requirements for properties of thesheet S to be manufactured or the configuration of the entire apparatus.In addition, in this case, a rotational speed of the rotation unit(number of rotation (rpm) per one minute) can be appropriately set inconsideration of conditions, such as throughput of the defibrationprocessing, a retention time of the raw material, an extent ofdefibration, a size of the gap, or the shape or the size of the rotaryunit, the stationary unit, and each of other members.

In addition, it is more preferable that the defibrating unit 20 has afunction of generating an air current (airflow) to suck in the rawmaterial 1 (defibration object) and/or discharge the defibratedmaterial. In this case, by the air current which is generated from thedefibrating unit 20 itself, the defibrating unit 20 can suck in the rawmaterial 1 together with the air current from the introduction port 21,perform the defibration processing, and transfer the defibrated materialto the discharge port 22. In the example illustrated in FIG. 1, thedefibrated material which is discharged from the discharge port 22 iscarried to the tube 82. In addition, when the defibrating unit 20 whichdoes not include an air current generating mechanism is used, providingan external mechanism which generates an air current that introduces theraw material 1 into the introduction port 21 or an air current whichsucks the defibrated material from the discharge port 22, is not aproblem.

1.1.1. Raw Material

In the specification, the raw material 1 indicates matter including rawmaterials of the sheet manufacturing apparatus 120, and examples thereofinclude material which is intertwined or bonded with the fibers, such aspulp sheets, paper sheets, waste paper sheets, tissue paper sheets,kitchen paper sheets, cleaning agents, filters, liquid absorbents,sound-absorbing materials, cushioning materials, matting materials, orcorrugated cardboard. In addition, the raw material 1 may include fibers(organic fibers, inorganic fibers, and organic-inorganic compositefibers) or the like which are constituted of rayon, lyocell, cupra,vinylon, acryl, nylon, aramid, polyester, polyethylene, polypropylene,polyurethane, polyimide, carbon, glass, or metal. In addition, in thesheet manufacturing apparatus 120 of the embodiment, it is possible touse a material which has been recycled one or more times as the rawmaterial 1, and particularly, to effectively use waste paper sheets.

The raw material 1 has a history. The history of the raw material 1 isinformation which is related to characteristics of the raw material 1,and specific examples thereof include a content of the additive agent inthe raw material 1, a type of the additive agent in the raw material 1,a length of the fibers in the raw material 1, or a material of thefibers in the raw material 1. Examples of information for simplyobtaining the information which is related to such characteristics ofthe raw material 1, include information which corresponds to the numberof times the raw material 1 has been recycled into sheets S in the past(hereinafter, simply referred to as a “number of recycling”),information which corresponds to the type (paper sheet, absorbent, orthe like) of the sheet S, and information which is related to the sheetmanufacturing apparatus which has been used in recycling. These piecesof information are ascertained by a marking given to the sheet S. Thesheet manufacturing apparatus 120 includes a marking unit 100 whichgives the marking to the sheet S, in the sheet forming unit 40 or on afurther downstream side from the sheet forming unit 40. In addition, thesheet manufacturing apparatus 120 includes an obtaining unit 8 whichobtains the history of the raw material 1 by reading the marking whichis given to the raw material 1. The marking unit 100 and the obtainingunit 8 will be described later.

The number of recycling is the number of times the raw material 1 hasbeen recycled into sheets S in the sheet manufacturing apparatus 120.Hereinafter, there will also be a case where the number of recycling issimply referred to as a “number of recycles”. Since the paper sheetwhich is manufactured by the wet type method has not been recycled bythe sheet manufacturing apparatus 120, the number of recycles is 0. Whenthe sheet S is manufactured in the sheet manufacturing apparatus 120 byusing the paper sheet which has been manufactured by the wet type methodas the raw material 1, the number of recycles is 1. In addition, whenthe sheet S is manufactured in the sheet manufacturing apparatus 120 byusing the sheet S in which the number of recycles is 1 as the rawmaterial 1, the number of recycles becomes 2. Even in a case of a sheetwhich is not manufactured by the sheet manufacturing apparatus 120, ifthe sheet manufacturing apparatus 120 can ascertain the number ofrecycles, the ascertained number is added to the number of recycles.Whether or not the sheet manufacturing apparatus 120 can ascertain thenumber of recycles depends on whether or not the obtaining unit 8 canobtain the history of the raw material. For example, even when the papersheet which is manufactured by the wet method by recycling the wastepaper sheet as the raw material is the raw material 1, if there is nomarking or if the sheet manufacturing apparatus 120 cannot ascertain thenumber, the characteristics of the raw material 1 cannot be ascertained.Therefore, the number of recycles cannot be considered as 1. In thiscase, the number of recycles is ascertained as 0, and the ascertainednumber of recycles is included in the information which corresponds tothe number of recycles. In addition, the number of recycling of the rawmaterial 1 which is not recycled yet by the sheet manufacturingapparatus 120 is 0. As an amount of the additive agent varies accordingto the information which corresponds to the number of recycling, evenwhen the amount of the additive agent included in the raw material 1changes according to the number of recycling, it is possible to set(change) the amount of the additive agent of the sheet S to a desiredamount.

The marking which is given to the sheet S may be not only a characterwhich shows the type or the like of the sheet S, the number of recyclesor type, but also a mark which is a sign or a symbol in other shapes aslong as the sign can make it possible to understand the number ofrecycles or the type. For example, if the marking is “A”, the amount ofthe additive agent may be decreased. In addition, the information whichcorresponds to the number of recycling may be not only the number ofrecycles, but also information which shows whether or not recycling isperformed, and whether the number of recycling is 0 or 1 or more.

The sheet manufacturing apparatus 120 varies the amount of the additiveagent which is fed by the addition unit 32 with respect to the rawmaterial 1, according to the history of the raw material 1. For example,when the raw material 1 has been recycled twice, the amount of theadditive agent which remains in the defibrated material tends to varyevery time recycling is performed. However, by varying the amount of theadditive agent according to the history of the raw material 1, it ispossible for the additive agent in the manufactured sheet S to be set tobe of a desired amount.

In addition, when the sheet S is manufactured by using the raw material1 which has the same history, it is possible to set the feed amount ofthe additive agent to be the same. The “same history” may have a scopewithin a range in which the feed amount of the additive agent can be setto be the same in accordance with required performance of the sheet S.

1.1.2. Defibrated Material

In the sheet manufacturing apparatus 120 of the embodiment, thedefibrated material which is used as a part of the material of the sheetS to be manufactured, is not particularly limited, and a wide range ofthe defibrated material can be used as long as the sheet S can beformed. The defibrated material includes the fiber which is obtained byperforming the defibration processing of the above-described rawmaterial, and examples of the fiber include natural fibers (animalfibers and vegetable fibers), or chemical fibers (organic fibers,inorganic fibers, and organic-inorganic composite fibers). Morespecifically, examples of the fibers included in the defibrated materialinclude cellulose fibers which are made of cotton, hemp, kenaf, flax,ramie, jute, Manila hemp, sisal hemp, conifer, or broadleaf tree, silk,or the animal fibers which are made of wool. These examples may be usedindependently, may be used by being appropriately mixed, or may be usedas regenerated fibers in which purification or the like is performed.The defibrated material becomes the material of the sheet S to bemanufactured, but may include at least one type of these fibers. Inaddition, the defibrated material (fibers) may be dried, or may containor impregnate the liquid, such as water or an organic solvent.Furthermore, in the defibrated material (fibers), various types ofsurface treatments may be performed.

The defibrated material has various characteristics in accordance withthe history of the raw material 1. Examples of the characteristics ofthe defibrated material are as follows: (1) in a case of a paper sheetin which the raw material 1 is not recycled yet, a resin is not includedin the defibrated material as the additive agent; (2) in a case of thesheet S in which the raw material 1 is recycled one or more times, theresin is adhered to the defibrated material as the additive agent; and(3) in a case of the sheet S in which the raw material 1 is recycled twoor more times, the fibers included in the defibrated material which areshorter than a paper sheet which is not used are included.

In the defibrated material which is used in the embodiment, moreadditive agents are adhered to the defibrated material in a case of agreater number of recycling of the raw material 1 compared to a case ofa fewer number of recycling. In addition, when the number of recyclingis high in this manner, the number of short fibers of the defibratedmaterial increases.

When the fiber included in the defibrated material which is used in theembodiment is one independent fiber, an average diameter (the longestlength in a direction which is perpendicular to a longitudinal directionwhen a cross section is not a circle, or a diameter of the circle(equivalent circle diameter) when the circle is assumed to be a circlewhich has an area equivalent to an area of the cross section) thereof is1 μm to 1000 μm, is preferably 2 μm to 500 μm, and is more preferably 3μm to 200 μm.

The length of the fiber included in the defibrated material which isused in the embodiment is not particularly limited, but as oneindependent fiber, the length (length of the disentangled defibratedmaterial (fibers) in the longitudinal direction, hereinafter, referredto as a “fiber length”) of the fiber along the longitudinal directionis, for example, 1 μm to 10 mm, is preferably 1 μm to 5 mm, and is morepreferably 3 μm to 2 mm. When the length of the fiber is short, there isa case where the strength of the sheet S is not sufficient, but if thelength is within the above-described range, it is possible to obtain thesheet S having sufficient strength. The length of the fiber along thelongitudinal direction may a distance (length of the fiber) between bothends of the fiber when both ends of the one independent fiber is pulledout not to be ruptured as necessary and the fiber is placed in asubstantially linear shape as the fiber is in a pulled-out state. Inaddition, the average length of the fiber as a length-weighted meanfiber length is 20 μm to 3600 μm, is preferably 200 μm to 2700 μm, andis more preferably 300 μm to 2300 μm. Furthermore, the length of thefiber may have unevenness (distribution).

In the specification, when the fiber is referred, there is a case whereone fiber is indicated, and there is a case where a coagulation of aplurality of fibers (for example, a state of being in a cotton shape) isindicated. In addition, when the defibrated material is referred, thematerial which is included in the plurality of fibers is indicated, anda meaning of the coagulation of the fibers and a meaning of a material(material in a powder-like shape or a cotton shape) which becomes thematerial of the sheet S are included.

1.2. Mixing Unit

Since the addition unit 32 which is provided in the sheet manufacturingapparatus 120 of the embodiment is provided in the mixing unit 30,first, the mixing unit 30 will be described. In addition, the additionunit 32 may be independent from the mixing unit 30, and may be disposedupstream of the mixing unit 30. The mixing unit 30 has a function ofmixing the defibrated material and the additive agent in the atmosphere.

In the specification, an expression “mixing the defibrated material andthe additive agent” means disposing the additive agent between thefibers which are included in the defibrated material, in a space(system) having a constant capacity.

If it is possible to mix the defibrated material (fibers) and theadditive agent, the configuration, the structure, and the mechanism ofthe mixing unit 30 is not particularly limited. In addition, even when amode of processing of mixing in the mixing unit 30 is batch processing,any of consecutive processing and sequential processing may be employed.In addition, the mixing unit 30 may be manually or automaticallyoperated. Furthermore, the mixing unit 30 mixes at least the defibratedmaterial and the additive agent, but may be in a mode in which othercomponents can be mixed.

The mixing unit 30 is provided on a further downstream side than theabove-described defibrating unit 20. In addition, the mixing unit 30 isprovided on a further upstream side than the sheet forming unit 40 whichwill be described later. Between the defibrating unit 20 and the mixingunit 30, a configuration of the classifying unit 63 or the screeningunit 35 may be included.

Examples of the processing of mixing in the mixing unit 30 can includemechanical mixing and hydrodynamic mixing. Examples of the mechanicalmixing include a method of introducing the fibers and the additive agentto a Henschel mixer or the like and stirring the fibers (defibratedmaterial) and the additive agent, and a method of enclosing the fibers(defibrated material) and the additive agent in a bag and shaking thebag. In addition, as the processing of hydrodynamic mixing, it ispossible to use a method of introducing the fibers (defibrated material)and the additive agent into the air current of the atmosphere or thelike and diffusing both the fibers and the additive agent in the aircurrent. In the method of introducing the fibers (defibrated material)and the additive agent in the air current of the atmosphere or the like,the additive agent may be fed into a tube or the like through which thefibers of the defibrated material flow (are carried) by the air current,or the fibers (defibrated material) may be fed into a tube or the likethrough which grains of the additive agent flow (are carried) by the aircurrent. In addition, in the method, a case where the air current in thetube or the like is a turbulent flow is more preferable since theefficiency of mixing increases.

As illustrated in FIG. 1, in the mixing unit 30, when the tube 86 forcarrying the defibrated material is employed, it is possible to employthe method of introducing the additive agent by the addition unit 32 ina state where the defibrated material flows by the air current in theatmosphere or the like. An example of a section of generating the aircurrent when the tube 86 is employed in the mixing unit 30, include ablower which is not illustrated, and it is possible to use anappropriate means (device) of generating the air current if theabove-described functions can be obtained.

In the sheet manufacturing apparatus 120 of the embodiment, the mixingunit 30 uses the dry method. Here, the “dry method” in mixing means astate where mixing is performed in the atmosphere (in the air), not inthe liquid. In the mixing unit 30, when the liquid is intentionallyadded to the extent not to interfere with the mixing operation, in thefollowing processing, it is preferable to add the liquid to the extentthat the energy or time for removing the liquid by heating or the likedoes not become excessive.

The performance of processing of the mixing unit 30 is not particularlylimited if it is possible to mix the defibrated material and theadditive agent, and the mixing unit 30 can be appropriately designed andadjusted in accordance with the manufacturing performance (throughput)of the sheet manufacturing apparatus 120. The adjustment of theperformance of processing of the mixing unit 30 can be performed bychanging a size or a charging amount of a processing container if themixing unit 30 is in the batch processing. In addition, when theabove-described tube 86 and the addition unit 32 are employed as themixing unit 30, it is possible to perform the adjustment of the mixingunit 30 by changing the flow of gas for carrying the defibrated materialand the additive agent in the tube 86, an introduce amount of thematerial, or a carry amount of the material. In addition, when the tube86 and the addition unit 32 are employed as illustrated in the drawingas the mixing unit 30, it is possible to sufficiently mix the defibratedmaterial and the additive agent.

1.2.1 Addition Unit

The mixing unit 30 includes the addition unit 32 which adds the additiveagent to the defibrated material which is defibrated in the defibratingunit 20. The addition unit 32 feeds the additive agent so that theamount thereof with respect to the raw material 1 varies according tothe history of the raw material 1 which is supplied to the defibratingunit 20. The addition unit 32 may be configured to have a feeder whichintroduces the additive agent to a circulation path of the defibratedmaterial.

It is possible to introduce the additive agent (including a case wherethe additive agent is a complex body) in a case where the tube 86 isemployed in the mixing unit 30 by an opening/closing operation of avalve or by hands of those skilled in the art. However, it is alsopossible to introduce the additive agent by using a screw feeder whichfunctions as the addition unit 32 as illustrated in FIG. 1 or a discfeeder which is not illustrated. Using these feeders is more preferablebecause it is possible to reduce the change in the add amount of theadditive agent in the flow direction of the air current. In addition,this is also similarly preferable when the additive agent is carried bythe air current and the defibrated material is introduced into the aircurrent. In the example in the drawing, the additive agent is suppliedto the tube 86 through a supply port 31 which is provided in the tube 86from the addition unit 32. Therefore, in the example in the drawing, themixing unit 30 is configured of a part of the tube 86, the addition unit32, and the supply port 31.

Here, a component other than the additive agent which can be suppliedfrom the addition unit 32 may be a material which can give theperformance that is required in the sheet S to the defibrated material.Examples of the component other than the additive agent includes thefiber, a coagulation inhibitor, a coloring material, a flame retardant,an organic solvent, surfactant, an antifungal and antiseptic agent,antioxidant, ultraviolet absorber, or oxygen absorber.

By using the plurality of screw feeders, in accordance with the historyof the raw material 1, it is possible to supply the additive agent tothe mixing unit 30 so that the add amount of the additive agent andother components varies. In addition, in addition to the history of theraw material 1, in order to satisfy the required performance of thesheet S, the add amount of the additive agent and other components maybe changed.

FIG. 2 illustrates a state where the addition unit 32 uses the pluralityof screw feeders. FIG. 2 is a schematic view illustrating the sheetmanufacturing apparatus 120 according to the embodiment in which amodification example of the mixing unit 30 is employed. When the pluraltypes of additive agents are separately supplied, or when the additiveagent and the components other than the additive agent are separatelysupplied, in this manner, the plurality of screw feeders may beprovided. This embodiment shown in FIG. 2 will be described in a section“1.2.1.2. Fiber”, but the addition unit 32 may include a resin feedingunit 32 a which feeds, for example, the resin which is the additiveagent, and a fiber feeding unit 32 b which feeds, for example, thefibers which is other components.

1.2.1.1. Additive Agent or the Like

The additive agent which is supplied from the addition unit 32 bonds theplurality of fibers which are included in the defibrated material toeach other. As the additive agent, it is possible to use the resin,starch (in particular, in a case of a wet method), and a water-solublebonding material. In addition, the additive agent may contain componentsother than the bonding components.

The additive agent can be supplied by a suitable amount with respect tothe defibrated material from the addition unit 32. The amount of theadditive agent which is fed by the addition unit 32 with respect to theraw material 1 varies according to the history of the raw material 1.For example, when the sheet S has been recycled twice, the amount of theadditive agent included in the defibrated material varies every timerecycling is performed. However, as the amount of the additive agentvaries according to the history of the raw material 1, it is possible toset the additive agent in the manufactured sheet S to a desired amount.

Influence of the history of the raw material 1 remains on the defibratedmaterial which is carried to the mixing unit 30. For example, when thesheet S which is already recycled is used as the raw material 1, moreadditive agents are adhered to the defibrated material than thedefibrated material which is not recycled. Here, in a case where thesheet S which has been recycled a greater number of times is used as theraw material 1, compared to a case where the sheet S which has beenrecycled a fewer number of times is used as the raw material 1, it ispossible to reduce the amount of the additive agent to be fed. Accordingto this, even when the sheet S which has been recycled a greater numberof times is used as the raw material 1, there being an excessive amountof additive agent in the sheet is prevented.

In general, general paper sheets are mainly made of hydrogen bondingwhich is considered as a main body by the wet method, and the amount ofthe additive agent which bonds the fibers to each other is small. Whensuch paper sheets are used as the raw material 1, it is possible to makethe sheet S having high strength or excellent water resistance by makingthe sheet S by the dry method by adding the additive agent which bondsthe fiber to the raw material 1. When the sheet is manufactured by thedry method, since the hydrogen bonding is not used or is small, the addamount of the additive agent is greater than in the wet method.Meanwhile, when the sheet S is used as the raw material 1, since theadditive agent is already included in the sheet S, the amount of theadditive agent becomes excessive when the same amount of the additiveagent as the amount of the additive agent which is added in the papersheet made by the wet method is added. When recycling is performed byusing the sheet S which is made by adding the additive agent once as theraw material 1, the amount of the additive agent is further increased. Acase where the amount of the additive agent is excessive means a casewhere it is not possible to regenerate the same sheet S as the sheet Sbefore regeneration. Here, by varying the amount of the additive agentto be fed according to the history of the raw material 1, for example,the number of recycling, there being an excessive amount of additiveagent in the sheet is prevented. Specifically, in a case where the sheetS which is manufactured by the sheet manufacturing apparatus 120 is usedas the raw material 1, that is, a case where the number of recycles is1, the amount of the additive agent included in the raw material isgreater than that in a case where the paper sheet which is manufacturedby the wet method is used as the raw material 1, that is, a case thenumber of recycles is 0. For this reason, the amount of the additiveagent to be fed is decreased.

In addition, for example, if it is possible to provide the classifyingunit 63 which will be described later on the upstream side of the mixingunit 30, and to completely remove the additive agent from the defibratedmaterial in the classifying unit 63, it is possible to set the feedamount of the additive agent to be constant. However, it is not possibleto completely remove the additive agent from the defibrated material inthe classifying unit 63. For this reason, even when the classifying unit63 is provided, it is not possible to supply the same amount of additiveagent every time recycling is performed in the addition unit 32.

In addition, since the sheet S is already recycled, only by evenlyreducing the amount of the additive agent, a case where the amount ofthe additive agent is decreased in the sheet S which has been recycledplural times is also considered. For this reason, the add amount of theadditive agent may also be changed in accordance with the number ofrecycling.

1.2.1.1.1. Resin

The additive agent which bonds the fibers to each other may include theresin. As a type of the resin, any of a natural resin and a synthesizedresin may be employed. In the sheet manufacturing apparatus 120 of theembodiment, it is preferable that the resin is a solid at a roomtemperature, it is preferable that the resin is the synthesized resin inwhich a melting point or the like is adjusted to be within apredetermined range for obtaining stabilized performance of the sheet Sto be manufactured, and it is more preferable that the resin is athermoplastic resin when the resin is used in bonding the fibers byheating in a heating unit 50.

The resin includes the resin for bonding the plurality of fibers. At thepoint of time when the additive agent is supplied to the tube 86, theplurality of fibers included in the defibrated material are not bondedto each other intentionally except a case where defibration is notsufficiently performed. The resin which is included in the additiveagent is melted or softened when passing through the heating unit 50which will be described later, and after this, the plurality of fibersare bonded to each other by hardening.

In addition, when the raw material 1 is recycled sheet S, the resin forbonding the plurality of fibers remains in the defibrated material, anda part thereof is adhered to the fibers. In this case, it is possible toadd the resin by an appropriate amount from the addition unit 32 inaddition to the resin which is adhered to the fibers so that the sheet Sin which the resin in the sheet S has a desired amount can bemanufactured.

Therefore, the amount of the resin in the sheet S is appropriately setin accordance with the history of the raw material 1 and the type of thesheet S to be manufactured. The proportion of the resin in the sheet Sis, for example, 5% by weight to 70% by weight. From the viewpoint ofobtaining an excellent mixture in the mixing unit 30 and making itdifficult to receive the additive agent descending due to gravity whenthe mixture is molded in a web shape, the proportion is preferably 5% byweight to 50% by weight. In the example in the drawing, the suppliedadditive agent is mixed with the defibrated material in the tube 86which configures the mixing unit 30.

Examples of the natural resin include rosin, dammar, mastic, copal,amber, shellac, Daemonorops draco, Sandarac, or colophonium. Theseexamples may be used independently or by being appropriately mixed. Inaddition, these examples may be appropriately chemically denatured.

In addition, examples of the thermoplastic resin among the synthesizedresins include an AS resin, an ABS resin, polypropylene, polyethylene,polyvinyl chloride, polystyrene, acrylic resin, polyester resin,polyethylene terephthalate, polyphenylene ether, polybutyleneterephthalate, nylon, polyamide, polycarbonate, polyacetal,polyphenylene sulfide, or polyether ether ketone.

These resins may be used independently or by being appropriately mixed.In addition, the resins may be copolymerized or denatured, and examplesof this type of resin include a styrene resin, an acrylic resin, astyrene-acrylic copolymer resin, an olefin resin, a vinyl chlorideresin, a polyester resin, a polyamide resin, a polyurethane resin, apolyvinyl alcohol resin, a vinyl ether resin, an N-vinyl resin, or astyrene-butadiene resin.

The additive agent may have a fibrous form, and may have a powder-likeshape. When the additive agent has a fibrous form, the fiber length ofthe additive agent is preferably equal to or less than the fiber lengthof the defibrated material. Specifically, the fiber length of theadditive agent is equal to or less than 3 mm, and is more preferablyequal to or less than 2 mm. When the fiber length of the additive agentis longer than 3 mm, there is a case where it is difficult to mix thedefibrated material with excellent uniformity. When the additive agenthas a powder-like shape, a grain size (diameter) of the additive agentis 1 μm to 50 μm, and is more preferably 2 μm to 20 μm. When the grainsize of the additive agent is less than 1 μm, there is a case where abonding force which bonds the fibers to each other in the defibratedmaterial deteriorates. When the grain size of the additive agent isgreater than 20 μm, there is a case where it is difficult to mix thedefibrated material with excellent uniformity, and there is a case whereunevenness is generated in the sheet S to be manufactured as an adheringforce to the defibrated material deteriorates and the additive agent isseparated from the defibrated material.

By using the resin as the additive agent, it is possible to manufacturethe sheet S having excellent water resistance and strength.

1.2.1.1.2. Coagulation Inhibitor

In addition to the resin which bonds the defibrated material, theadditive agent may include the coagulation inhibitor for suppressingcoagulation between the fibers in the defibrated material or between theresins in the additive agent. In addition, when the coagulationinhibitor is included in the additive agent, it is preferable tointegrate the resin and the coagulation inhibitor. In other words, whenthe coagulation inhibitor is included in the additive agent, it ispreferable that the additive agent is a complex body which has the resinand the coagulation inhibitor integrated therein.

Specific examples of materials of the coagulation inhibitor includesilica, titanium oxide, aluminum oxide, zinc oxide, cerium oxide,magnesium oxide, zirconium oxide, strontium titanate, barium titanate,or calcium carbonate. In addition, a part (for example, titanium oxideor the like) of the exemplified materials of the coagulation inhibitoris the same as the material of the coloring material, but is differentin that the grain size of the coagulation inhibitor is smaller than thegrain size of the coloring material. For this reason, the coagulationinhibitor does not greatly influence a color tone of the sheet S to bemanufactured, and can be distinguished from the coloring material.However, when the color tone of the sheet S is adjusted, even when thegrain size of the coagulation inhibitor is small, since there is a casewhere some effects, such as light scattering, are generated, it ispreferable to consider such effects.

1.2.1.1.3. Coloring Material

In addition to the resin which bonds the fibers of the defibratedmaterial, the additive agent may include the coloring material. Inaddition, when the coloring material is included in the additive agent,it is preferable to integrate the resin and the coloring material. Inother words, it is preferable that the additive agent is a complex bodyin which the resin and the coloring material are integrated. Inaddition, even when the complex body includes the above-describedcoagulation inhibitor, the complex body can have the resin, the coloringmaterial, and the coagulation inhibitor integrated. In other words, theadditive agent may include the complex body in which the resin, thecoagulation inhibitor, and the coloring material are integrated.

The color and the type of pigments are not particularly limited, and itis possible to use pigments having various colors (white, blue, red,yellow, cyan, magenta, yellow, black, or special colors (pearl ormetallic luster)) which are generally used in ink. The pigments may beinorganic pigments, and may be organic pigments. As the pigments, it ispossible to use known pigments described in JP-A-2012-87309, or inJP-A-2004-250559. In addition, white pigments, such as zinc white,titanium oxide, antimony white, zinc sulfide, clay, silica, whitecarbon, talc, or alumina white, may be used. These pigments may be usedindependently, and may be used by being appropriately mixed. Inaddition, when the white pigments are used, among the above-describedexamples, it is more preferable to use the pigments which are made ofpowder including grains (pigment grains) which has titanium oxide as amain component since it is easy to enhance the whiteness of the sheet Sto be manufactured with a small compound amount, by a high refractiveindex of titanium oxide.

1.2.1.1.4. Water-Soluble Bonding Agent

In a case of the wet method, it is possible to use water-soluble bondingagent as the additive agent. Examples of the water-soluble bonding agentinclude polyacrylamide, polyamide-epichlorohydrin resin, polyvinylalcohol, starch, or alkyl ketene dimer. In addition, the water-solublebonding agent is called a paper strengthening agent.

1.2.1.2. Fiber

The components other than the additive agent which are supplied from theaddition unit 32 may include the fiber. As a type of the fiber, thefiber which is necessary for obtaining a desired sheet S may beappropriately selected among the fibers described above in “1.1.1. RawMaterial”. It is preferable that the fiber is a fiber which is the sametype as the fiber included in the raw material 1. This is because it ispossible to manufacture the sheet S having the same function as that ofthe raw material 1. In addition, the fiber may be a fiber which canreinforce the sheet S. For example, a fiber which has higher strengththan that of the fiber included in the raw material 1 may be employed,or a longer fiber may be employed. Otherwise, the fiber which can beobtained by defibrating the raw material 1 in which the number ofrecycles is 0 may be employed. By selecting such fibers, it is possibleto reinforce strength of the sheet S.

When the fibers are supplied from the addition unit 32, the sheetmanufacturing apparatus 120 which employs the modification example ofthe mixing unit 30 illustrated in FIG. 2 may be employed.

As illustrated in FIG. 2, the addition unit 32 may include the resinfeeding unit 32 a for supplying the resin and the fiber feeding unit 32b for supplying the fibers, to the defibrated material which isdefibrated by the defibrating unit 20. In this case, for example, theresin feeding unit 32 a is the addition unit 32 in FIG. 1 and can supplythe resin to the defibrated material by a suitable amount, and the fiberfeeding unit 32 b can supply the fibers to the defibrated material by asuitable amount.

The resin feeding unit 32 a and the fiber feeding unit 32 b can use theabove-described configuration (screw feeder or the like) as the additionunit 32 in FIG. 1.

The feed amount of the fibers in the fiber feeding unit 32 b can bechanged according to the history of the raw material 1. In addition, thefeed amount of the fibers in the fiber feeding unit 32 b may be greaterin a case where the sheet S which has been recycled a greater number oftimes is used as the raw material 1 compared to a case where the sheet Swhich has been recycled a fewer number of times is used as the rawmaterial 1. For example, when the sheet S in which the number ofrecycles is 0 or 1 is used as the raw material 1, the fibers are not fedin the fiber feeding unit 32 b, and when the number of recycles is 2,the fibers are fed in the fiber feeding unit 32 b. When the number ofrecycling is high, the proportion of the additive agent increases asdescribed above, and the proportion of the fibers in the defibratedmaterial decreases. For this reason, it is possible to enhance theproportion of the fibers in the defibrated material by feeding thefibers, and to prevent the amount of other additive agents with respectto the fibers from being excessive.

In addition, when the sheet S is recycled plural times, since theproportion of the fibers which become shorter every time the fibersincluded in the defibrated material are recycled increases, by supplyingthe fibers which are not recycled or the fibers which has been recycleda fewer number of times according to the history of the raw material 1,and further, by varying the supply amount thereof in accordance with thenumber of recycling, it is possible to reinforce the sheet S, and tomanufacture the sheet S having a desired strength.

The proportion of the fibers or the length of the fibers in thedefibrated material can be decided according to the history of the rawmaterial 1.

1.3. Sheet Forming Unit

The sheet forming unit 40 forms the sheet S by bonding the plurality offibers to each other via the additive agent.

The mixture, which is made by mixing the additive agent into thedefibrated material in the mixing unit 30, forms the sheet S by bondingthe fibers to each other via the additive agent, in the sheet formingunit 40.

In addition, in the specification, a case where the sheet S is referredis a case where a structure in which the plurality of fibers are bondedto each other via the resin in a two-dimensional or a three-dimensionalmanner, or the fibers are bonded by the hydrogen bonding.

A shape of the sheet S in the specification is not limited to a sheetshape, and may be a film shape, a board shape, a web shape, or an unevenshape. In addition, the sheet S in the specification can be divided intoa paper sheet and a non-woven fabric. Examples of the paper sheetinclude a state of being formed in a sheet shape by using the pulp orthe waste paper sheet as the raw material, and include a recording papersheet for writing or printing, a wall paper sheet, a wrapping papersheet, a color paper sheet, a drawing paper sheet, and a Kent papersheet. The non-woven fabric is thicker in thickness and weaker instrength than the paper sheet, and includes general non-woven fabrics,fiber boards, tissue paper sheets, kitchen paper sheets, cleaningagents, filters, liquid absorbents, sound-absorbing materials,cushioning materials, or matting materials.

The sheet S may have the same function as that of the sheet S which isused in the raw material 1. When a copy paper sheet for business is usedas the raw material 1, the sheet S may be the copy paper sheet forbusiness. In this manner, it is possible to regenerate the copy papersheet for business into a copy paper sheet for business which has thesame function even when recycling is performed plural times.

Examples of the sheet forming unit 40 can include a deposition unit 75,a pressing unit 60, a heating unit 50, and a cutting unit 90. These willbe described later.

1.4. Operation Effect

According to the sheet manufacturing apparatus 120 of the embodiment, byvarying the amount of the additive agent according to the history of theraw material 1, it is possible for the additive agent in the sheet S tobe set to be of a desired amount. For example, when the sheet S has beenrecycled twice, the amount of the additive agent included in thedefibrated material varies every time recycling is performed, but bydoing so, it is possible for the additive agent in the sheet S to be setto be of a desired amount.

1.5. Other Configurations

With reference to FIGS. 1 to 3, other configurations of the sheetmanufacturing apparatus 120 will be described. FIG. 3 is a functionalblock diagram illustrating the sheet manufacturing apparatus 120according to the embodiment.

The sheet manufacturing apparatus 120 of the embodiment can includevarious configurations, such as, the obtaining unit 8, a supplying unit9, a crushing unit 10, the classifying unit 63, the screening unit 35,the marking unit 100, and a control unit 110, in addition to thedefibrating unit 20, the mixing unit 30, and the sheet forming unit 40which are described above. In addition, in addition to theabove-described addition unit 32, the mixing unit 30 can include arefining unit 70. Furthermore, the sheet forming unit 40 can includevarious configurations, such as the deposition unit 75, the pressingunit 60, the heating unit 50, and the cutting unit 90. Each of theseconfigurations will be described below. In addition, a plurality ofobtaining units 8, supplying units 9, crushing units 10, defibratingunits 20, classifying units 63, screening units 35, mixing units 30,refining units 70, sheet forming units 40, deposition units 75, pressingunits 60, heating units 50, cutting units 90, and marking units 100, maybe provided as necessary.

1.5.1. Obtaining Unit

The sheet manufacturing apparatus 120 of the embodiment may include theobtaining unit 8. The obtaining unit 8 obtains the history of the rawmaterial 1. The obtaining unit 8 obtains various types of history whichcan be read from the raw material 1. The history is various pieces ofinformation which is described in “1.1.1. Raw Material”, but theobtaining unit 8 includes a section of reading these various pieces ofinformation. For example, the obtaining unit 8 may obtain the history ofthe raw material 1 by reading the marking which is given to the sheet Sin the marking unit 100 which will be described later. The obtainingunit 8 is, for example, an optical sensor, and reads the marking byemitting light with respect to the marking and receiving reflectedlight.

In the sheet manufacturing apparatus 120 illustrated in FIG. 1, theobtaining unit 8 is disposed at a position which is the upstream side ofthe defibrating unit 20, and at which the raw material 1 is supplied tothe sheet manufacturing apparatus 120. The history of the raw material 1obtained by the obtaining unit 8 is output to the control unit 110.

1.5.2. Supplying Unit

The sheet manufacturing apparatus 120 of the embodiment may include thesupplying unit 9. In the sheet manufacturing apparatus 120 illustratedin FIG. 1, the supplying unit 9 is positioned on the upstream side ofthe defibrating unit 20, and supplies the raw material 1 to thedownstream side. The supplying unit 9 may supply the raw material 1 tothe crushing unit 10.

The supplying unit 9 is an automatic feeding device for sequentiallyfeeding the raw material 1 into the crushing unit 10.

Based on the history of the raw material 1 obtained by the obtainingunit 8, the supplying unit 9 may screen various types of the rawmaterials 1 having the same level of history, store the raw material 1by the type, and supply the raw material 1 by the type to the crushingunit 10, according to a command of the control unit 110. When theplurality of raw materials 1 is sequentially supplied from the supplyingunit 9, by sequentially supplying the raw material 1 having the samelevel of history downstream, it is possible to supply the same amount ofthe additive agent, and to sequentially manufacture the sheets S havingthe same level of performance. In addition, when the raw materials 1 aresupplied from the supplying unit 9 one by one, it is possible to varythe amount of the additive agent every raw material 1, and tomanufacture the sheet S having a desired amount of the additive agent.

1.5.3. Crushing Unit

The sheet manufacturing apparatus 120 of the embodiment may include thecrushing unit 10. In the sheet manufacturing apparatus 120 illustratedin FIG. 1, the crushing unit 10 is disposed on the upstream side of thedefibrating unit 20. The crushing unit 10 cuts out the raw material 1,such as the pulp sheet or the fed sheet (for example, the waste papersheet having an A4 size) in the air, and makes the raw material 1 adefibration object. The shape or the size of the defibration object isnot particularly limited, but for example, the raw material 1 may be cutout to several centimeters square. In the example in the drawing, thecrushing unit 10 includes a crushing blade 11, and it is possible to cutout the fed raw material 1 by the crushing blade 11.

A specific example of the crushing unit 10 includes a shredder. In theexample in the drawing, the defibration object which is cut out by thecrushing unit 10 is transferred to the defibrating unit 20 via a tube 81after being received by a hopper 15. The tube 81 communicates with theintroduction port 21 of the defibrating unit 20.

1.5.4. Classifying Unit

In the sheet manufacturing apparatus 120 illustrated in FIG. 1, theclassifying unit 63 is disposed on the upstream side of the mixing unit30 and a downstream side of the defibrating unit 20. The classifyingunit 63 separates the additive agent, the resin grains, and the inkgrains, which are included in the raw material 1 and have a relativelysmall size or a low density, and removes these from the defibratedmaterial. According to this, it is possible to enhance an occupancyratio of the fibers which have a relatively large size or a high densityin the defibrated material.

As the classifying unit 63, it is preferable to use an airflowclassifier. The airflow classifier generates a swirling air current andperforms separation in accordance with a difference between acentrifugal force and a centrifugal force received according to the sizeand the density of the classified materials. By adjusting the speed ofthe air current and the centrifugal force, it is possible to adjust aclassification point. Specifically, as the classifying unit 63, acyclone, an elbow jet, or an Eddy classifier, is used. In particular,since the cyclone has a simple structure, it is possible toappropriately use the cyclone as the classifying unit 63. Hereinafter, acase where the cyclone is used as the classifying unit 63 will bedescribed.

The classifying unit 63 includes an introduction port 64, a cylinderunit 65 to which the introduction port 64 is connected, an inverse coneunit 66 which is positioned below the cylinder unit 65 and continues tothe cylinder unit 65, a lower discharge port 67 which is provided in thecenter of a lower part of the inverse cone unit 66, and an upperdischarge port 68 which is provided in the center of an upper part ofthe cylinder unit 65.

In the classifying unit 63, the air current which has the defibratedmaterial introduced from the introduction port 64 therein changes into acircumferential movement by the cylinder unit 65. Accordingly, thecentrifugal force is applied to the introduced defibrated material, andit is possible to separate the fibers having a higher density than thatof the resin grains or the ink grains in the defibrated material, or theresin grains or the ink grains having a lower density than that of thefibers in the defibrated material. The component having more fibers aredischarged from the lower discharge port 67, and introduced to thescreening unit 35 through a tube 83. Meanwhile, the resin grains or theink grains are discharged to the outside of the classifying unit 63through a tube 84 from the upper discharge port 68. In the example inthe drawing, the tube 84 is connected to a receiving unit 69, and thefine powder is collected to the receiving unit 69.

In addition, it is described that the fibers and fine powder areseparated by the classifying unit 63, but a complete separation is notpossible. For example, there is a case where the fibers having arelatively small size and a low density among the fibers, are dischargedto the outside together with the fine powder. In addition, the finepowder which has a relatively high density or is bonded to the fibersamong the fine powder, is introduced to the screening unit 35 togetherwith the fibers.

In addition, since the fine powder, such as the resin grains or the inkgrains, is not included when the raw material is not the waste papersheet, but the pulp sheet, the classifying unit 63 may not be providedin the sheet manufacturing apparatus 120. Inversely, when the rawmaterial is the waste paper sheet, since the color tone of the sheet tobe manufactured is excellent, it is preferable that the sheetmanufacturing apparatus 120 is configured to include the classifyingunit 63. In addition, since there are many cases where the paper sheetacquires more excellent whiteness than that of the non-woven fabric,there is a case where it is better to provide the classifying unit 63when manufacturing the paper sheet, and not to provide the classifyingunit 63 when manufacturing the non-woven fabric.

1.5.5. Screening Unit

The sheet manufacturing apparatus 120 of the embodiment may include thescreening unit 35. The screening unit 35 can screen the defibratedmaterial which is defibration-processed in the defibrating unit 20 bythe length of the fibers. In addition, in the above-describedclassifying unit 63, it is described that the fine resin grains or thelike are removed, but the screening unit 35 may have such a function.Therefore, the screening unit 35 is provided downstream of thedefibrating unit 20, and further upstream of the refining unit 70.

As the screening unit 35, it is possible to use a sieve. Here, thescreening unit 35 includes a net (filter, screen), and screens materialshaving a size that can pass through the net and materials having a sizethat cannot pass through the net. The screening unit 35 includes anintroduction port 36 and a discharge port 37. The screening unit 35 canbe configured similarly to the refining unit 70 which will be describedlater. However, unlike the refining unit 70, the screening unit 35 doesnot allow all of the introduced materials to pass through, and has afunction of removing some components. An example of the screening unit35 includes a cylindrical sieve which can rotate by a motor. The net ofthe screening unit 35 can use a mesh, an expand metal which is made byexpanding a metal plate having a notch, and a punching metal which hasholes formed by a press machine or the like on the metal plate.

By providing the screening unit 35, it is possible to divide the fibersor grains having a smaller size than an aperture of the net, and thefibers, non-defibrated pieces, or a lump which has a greater size thanthe aperture of the net. The screened material can be used by beingselected in accordance with the sheet S to be manufactured. Thedefibrated material which passes through the sieve of the screening unit35 is transferred to an introduction port 71 of the refining unit 70 viathe tube 86 of the mixing unit 30 after being received by a hopper 38.In addition, the material which is removed by the screening unit 35 mayreturn to the crushing unit 10 from the discharge port 37.

1.5.6. Refining Unit

The sheet manufacturing apparatus 120 may include the refining unit 70.In the sheet manufacturing apparatus 120 illustrated in FIG. 1, therefining unit 70 and the deposition unit 75 are disposed downstream ofthe addition unit 32. In FIG. 3, the refining unit 70 is included in themixing unit 30 together with the addition unit 32.

The refining unit 70 introduces the mixture which passes through thetube 86 of the mixing unit 30 from the introduction port 71, and sendsdown (drop) the mixture while scattering the mixture in the air. Inaddition, in this example, the sheet manufacturing apparatus 120includes the deposition unit 75, deposits the mixture which is sent downfrom the refining unit 70 in the air by the deposition unit 75, andforms a web W shape.

The refining unit 70 refines the intertwined defibrated material(fibers). Furthermore, when the resin of the additive agent suppliedfrom the addition unit 32 has a fibrous form, the refining unit 70refines the intertwined resin. In addition, the refining unit 70performs an operation of uniformly depositing the mixture in thedeposition unit 75 which will be described later. In other words, theword “refine” includes an operation of making the intertwined materialcome apart and the operation of uniformly depositing the mixture. Inaddition, the refining unit 70 achieves an effect of uniformlydepositing the material if there is no intertwined materials.

As the refining unit 70, the sieve is used. An example of the refiningunit 70 includes a rotary sieve which can rotate by the motor. Here, the“sieve” of the refining unit 70 may not have a function of screening acertain target. In other words, the “sieve” which is used as therefining unit 70 means a sieve which is provided with the net (filter,screen), and the refining unit 70 may drop down all of the defibratedmaterials and the additive agents which are introduced to the refiningunit 70.

1.5.7. Deposition Unit

The sheet manufacturing apparatus 120 may include the deposition unit75. The defibrated material and the additive agent which pass throughthe refining unit 70 are deposited in the deposition unit 75. Asillustrated in FIG. 1, the deposition unit 75 may include a mesh belt76, a stretching roller 77, and a suction mechanism 78. The depositionunit 75 may be configured to include a tension roller or the like whichis not illustrated.

The deposition unit 75 forms the web W in which the mixture which issent down from the refining unit 70 is deposited in the air (correspondsto the web forming process when matching the refining unit 70). Thedeposition unit 75 has a function of depositing the mixture which isuniformly scattered in the air by the refining unit 70, on the mesh belt76. In addition, a moisture-adjusting unit may be provided on adownstream side of the deposition unit 75 so as to adjust an amount ofmoisture of the mixture which is sent down from the refining unit 70.

Below the refining unit 70, the endless mesh belt 76 in which the meshthat stretches by the stretching roller 77 (in the embodiment, fourstretching rollers 77) is formed is disposed. As at least one of thestretching rollers 77 self-rotates, the mesh belt 76 moves in onedirection.

In addition, vertically below the refining unit 70, via the mesh belt76, the suction mechanism 78 which functions as a sucking unit whichgenerates the air current vertically downward is provided. By thesuction mechanism 78, it is possible to suck in the mixture which isscattered in the air by the refining unit 70 onto the mesh belt 76.Accordingly, it is possible to suck in the mixture which is scattered inthe air, and to increase a discharge speed from the refining unit 70. Asa result, it is possible to enhance productivity of the sheetmanufacturing apparatus 120. In addition, by the suction mechanism 78,it is possible to form a downflow in a descending path of the mixture,and to prevent the defibrated material or the additive agent from beingintertwined during the descending.

By sending down the mixture from the refining unit 70 while moving themesh belt 76, it is possible to form the elongated web W in which themixture is uniformly deposited. Here, an expression “uniformly deposit”means a state where the deposited materials have substantially the samethickness and substantially the same density. However, since all of thedeposited materials are not manufactured as the sheet S, the part whichbecomes the sheet S may be uniform. An expression “ununiformly deposit”means a state where the deposition is not performed uniformly.

If the mesh belt 76 can be made of a metal, a resin, cloth, or anon-woven fabric, the mixture can be deposited, and the mesh belt 76allows the mixture to pass through the air current, any type of meshbelt may be employed. A hole diameter (diameter) of the mesh belt 76 is,for example, 60 μm to 250 μm. When the hole diameter of the mesh belt 76is less than 60 μm, there is a case where it is difficult to form thestabilized air current by the suction mechanism 78. When the holediameter of the mesh belt 76 is greater than 250 μm, there is a casewhere the fibers of the mixture enter the mesh, and unevenness of thefront surface of the sheet S to be manufactured increases. In addition,the suction mechanism 78 can be configured to form an enclosure box inwhich a window having a desired size is opened below the mesh belt 76,to suck in the air other than from the window, and to make the inside ofthe box into a negative pressure by the external air.

As described above, by passing the refining unit 70 and the depositionunit 75 (web forming process), the web W in a state of containing a lotof air and being softly swollen is formed. Next, as illustrated in FIG.1, the web W which is formed on the mesh belt 76 is transferred by therotational movement of the mesh belt 76. In this example, the web Wwhich is formed on the mesh belt 76 is transferred to the pressing unit60, the heating unit 50, the cutting unit 90, and the marking unit 100.

1.5.8. Pressing Unit

The sheet manufacturing apparatus 120 of the embodiment may include thepressing unit 60. In the sheet manufacturing apparatus 120 illustratedin FIG. 1, the pressing unit 60 is disposed on the downstream side ofthe mixing unit 30 and the upstream side of the heating unit 50. Thepressing unit 60 passes the refining unit 70 and the deposition unit 75,is formed in a sheet shape, and performs pressing without heating theweb W. Therefore, the pressing unit 60 may not include a heatingsection, such as a heater. In other words, the pressing unit 60 isconfigured to perform so-called calendering processing.

In the pressing unit 60, by pressing (compressing) the web W, aninterval (distance) between the fibers in the web W contracts, and thedensity of the web W increases. As illustrated in FIG. 1, the pressingunit 60 is configured to nip the web W by the rollers, and to press theweb W, and includes a pair of pressing rollers 61. Each of center axesof the pair of pressing rollers 61 is parallel to each other. Inaddition, the pressing unit 60 of the sheet manufacturing apparatus 120of the embodiment is provided with a first pressing unit 60 a which isdisposed on the upstream side in a transfer direction of the web W, anda second pressing unit 60 b which is disposed on the downstream side ofthe first pressing unit 60 a, and each of the first pressing unit 60 aand the second pressing unit 60 b is provided with a pair of pressingrollers 61. In addition, between the first pressing unit 60 a and thesecond pressing unit 60 b, a guide G which assists the transfer of theweb W is disposed.

In the pressing unit 60, since only pressing is performed withoutheating, the resin in the additive agent does not melt. In addition, inthe pressing unit 60, only pressing is performed without heating, evenwhen the moisture-adjusting unit is provided on the upstream side, here,the moisture in the mixture is mostly not removed.

In the sheet manufacturing apparatus 120 of the embodiment, the pressingunit 60 (first pressing unit 60 a and second pressing unit 60 b) and theheating unit 50 (first heating unit 50 a and second heating unit 50 b)are provided. In addition, in the example, the heating unit 50 performspressing with respect to the web W, but it is preferable that a pressingforce of the pressing unit 60 is set to be greater than a pressing forceby the heating unit 50. For example, it is preferable that the pressingforce of the pressing unit 60 is set to be 500 kgf to 3000 kgf, and thepressing force of the heating unit 50 is set to be 30 kgf to 200 kgf. Inthis manner, by setting the pressing force of the pressing unit 60 to begreater than that by the heating unit 50, it is possible to sufficientlyshorten the distance between the fibers included in the web W by thepressing unit 60, and by heating and pressing in this state, it ispossible to form a thinner sheet which has a high density and highstrength.

In addition, in the sheet manufacturing apparatus 120 of the embodiment,as illustrated in FIG. 1, the diameter of the pressing roller 61 is setto be greater than the diameter of a heating roller 51. Since thediameter of the pressing roller 61 is greater than the diameter of theheating roller 51, it is possible to bite the web W in a state of notbeing compressed yet, and to efficiently transfer the web W. Meanwhile,since the web W which passes through the pressing roller 61 is in acompressed state, and is likely to be transferred, the diameter of theheating roller 51 which is disposed on the downstream side may besmaller than that of the pressing roller 61. In addition, the diameterof the heating roller 51 and the diameter of the pressing roller 61 areappropriately set in accordance with the thickness or characteristics ofthe web W to be manufactured.

In addition, the pressing unit 60 which is illustrated in the drawing isan example of a case where two pairs of pressing rollers 61 areprovided. However, when the pressing unit 60 is employed and thepressing roller 61 is employed in the pressing unit 60, the number orthe disposition of the pressing roller 61 is not limited, and it ispossible to have an arbitrary configuration within a range where theabove-described operation is achieved.

Furthermore, between the pressing roller 61 of the pressing unit 60 andthe heating roller 51 of the heating unit 50, a member with which theweb W can come into contact is only the guide G which functions as a webreceiving member that can support the web W from below. Therefore, thedistance between the pressing roller 61 and the heating roller 51 can beshortened. In addition, since the pressed web W is quickly heated andpressed, it is possible to suppress a spring back of the web W, and toform the sheet having high strength.

When the pressing unit 60 (pressing roller 61) and the heating unit 50(heating roller 51) are provided the above-described configuration, thepressing unit 60 and the heating unit 50 are for the sheet which is thinand has a high density and high strength. For example, the pressing unit60 and the heating unit 50 are for the paper sheet rather than thenon-woven fabric.

1.5.9. Heating Unit

The sheet manufacturing apparatus 120 of the embodiment is provided withthe heating unit 50. The heating unit 50 is provided on the furtherdownstream side than the above-described pressing unit 60.

The heating unit 50 heats the mixture which is mixed in theabove-described mixing unit 30, and bonds the plurality of fibers toeach other via the additive agent. In addition, when the moisture isadded in the mixture, a state where the hydrogen bonding is formedbetween the fibers may be formed. The mixture of which the moisture isadjusted, may be formed, for example, in a web shape. In addition, theheating unit 50 may have a function of forming the mixture in apredetermined shape.

In the specification, an expression “bond the plurality of fibers toeach other via the additive agent” means a state where the fibers andthe additive agent in the defibrated material are unlikely to beseparated from each other or a state where the resin of the additiveagent is disposed between the fibers, and it is difficult to separatethe fibers from each other via the additive agent. In addition, thebonding is a concept which includes adhesion, and includes a state wheretwo or more types of objects are in contact with each other and unlikelyto be separated from each other. In addition, when the fibers are bondedto each other via the complex body, the fibers may be parallel to eachother and intersect each other, or the plurality of fibers may be bondedto one fiber. In addition, an expression “the fiber is hydrogen-bonded”means that the plurality of fibers are combined (bonded) to each otherpartially or entirely by the hydrogen bonding.

In a case where the resin which is one of the constituent components ofthe additive agent is the thermoplastic resin, if heating is performedto reach a glass transfer temperature (softening point) or a temperaturewhich is equal to or greater than the vicinity of a melting point, theresin is softened or melted, and after this, when the temperaturedecreases, the resin is hardened. As the resin is hardened, comes intocontact with the fibers to be intertwined, and is solidified, it ispossible to bond the fibers and the additive agent to each other. Inaddition, as other fibers are bonded when the resin is solidified, thefibers are bonded to each other. In addition, it is preferable that theglass transfer temperature, the melting point, or the softening point ofthe resin is lower than a decomposition temperature and a carbonizationtemperature of the fibers, and in order to achieve such a relationship,it is preferable to select by combining both types of the resin andfibers.

Meanwhile, when the moisture is adjusted downstream of the depositionunit 75, the heating unit 50 partially or entirely evaporates themoisture included in the mixture. Accordingly, water molecules which areinterposed between the fibers is reduced (removed). According to this,it is possible to form the hydrogen bonding between the fibers.Therefore, it is preferable that the heating unit 50 is set to atemperature which is equal to or greater than a boiling point of thewater, but if it is possible to form the hydrogen bonding, the heatingunit 50 may be a unit which heats the temperature to the temperaturewhich is equal to or less than the boiling point of the water.

In addition, in the heating unit 50, pressure may be applied in additionto applying the heat to the mixture. In this case, according to a targetstate of the sheet S, the heating unit 50 has a function of forming themixture in a predetermined shape. The level of the applied pressure isappropriately adjusted by the type of the sheet S to be formed, but canbe 100 kPa to 1 MPa. If the applied pressure is low, it is possible toobtain a sheet having a high porosity, and if the applied pressure ishigh, it is possible to obtain a sheet having a low porosity (highdensity).

Specific examples of the heating unit 50 include a heating roller(heater roller), a heat press forming machine, a hot plate, a warm airblower, an infrared heater, or a flash fixing device. In the sheetmanufacturing apparatus 120 of the embodiment illustrated in FIG. 1, theheating unit 50 is configured of the heating roller 51. In the exampleof the drawing, the heating unit 50 heats the pressed web W by thepressing unit 60. In addition, the heating unit 50 may have a functionof pressing the web W. By heating the web W, it is possible to bond thefibers included in the web W to each other via the additive agent andthe hydrogen bonding.

In the example in the drawing, the heating unit 50 is configured to nipthe web W by the rollers, heat the web W, and press the web W, andincludes one pair of heating rollers 51. Each of the pair of heatingrollers 51 is parallel to the center axis. In addition, the heating unit50 can be configured of the rollers or the like, and the heating unit 50can also be configured of a planar pressing unit. Here, detaildescription thereof will be omitted, but when the planar pressing unitis used as the heating unit 50, this case is for a relatively thicksheet, for example, the non-woven fabric having a low density. Since thecontact time with respect to the web W takes longer in a case where theplanar pressing unit is used compared to a case where the heating rolleris used, this case is for a sheet which is thick and takes time totransfer the heat to the entire web. In addition, the pressing unit 60may not be provided on an upstream side of the planar pressing unit. Inthis case, since the compression to have a high density by the pressingunit 60 is not performed, this case is for the sheet which has arelatively low density. When the planar pressing unit is used, this caseis for the non-woven fabric rather than the paper sheet.

The heating unit 50 is provided with the first heating unit 50 a whichis disposed on the upstream side of the web W in the transfer direction,and the second heating unit 50 b which is disposed on the downstreamside of the first heating unit 50 a, and each of the first heating unit50 a and the second heating unit 50 b is provided with one pair ofheating rollers 51. In addition, between the first heating unit 50 a andthe second heating unit 50 b, the guide G which assists the transfer ofthe web W is disposed.

In addition, in the center unit of a core bar, as the heating section, aheating material which is not illustrated, such as a halogen heater, isprovided. The heating roller 51 and the heating material respectivelyobtain the temperature by a temperature detecting unit which is notillustrated based on the obtained temperature, and are controlled by anON-OFF control of the heating material or a control of electric energy.Accordingly, it is possible to retain the surface temperature of theheating roller 51 to be a predetermined temperature. By allowing the webW to pass through between the heating rollers 51, it is possible to heatand press the transferred web W. In addition, the heating section is notlimited to the halogen heater or the like, and for example, a heatingsection by a non-contact heater or a heating section by warm air may beemployed.

In addition, the heating unit 50 which is illustrated in the drawing isan example of a case where two pairs of heating rollers 51 are provided.However, the number or the disposition of the heating rollers 51 is notlimited, and it is possible to be arbitrarily configured within a rangewhere the above-described operation is achieved. In addition, theconfiguration (thickness or material of a releasing layer, an elasticlayer, and a core bar, outer diameter of the roller) of the heatingrollers 51 of each heating unit 50, or a load applied bypressure-welding the heating roller 51, may vary according to eachheating unit 50.

As described above, as passing the heating unit 50 (heating process),the resin included in the additive agent is melted, easily becomesentangled with the fibers in the defibrated material, and the fibers arebonded to each other. In addition, the fibers may be combined to eachother by the hydrogen bonding. The mixture of the defibrated materialand the additive agent becomes the sheet S by passing the heating unit50.

1.5.10. Cutting Unit

In the sheet manufacturing apparatus 120 of the embodiment, on adownstream side of the heating unit 50, a first cutting unit 90 a and asecond cutting unit 90 b are disposed as the cutting unit 90 which cutsthe sheet S in a direction which intersects the transfer direction ofthe web W (the web W which passes the heating unit 50 is the sheet S).The cutting unit 90 can be provided as necessary.

The first cutting unit 90 a is provided with a cutter, and cuts out thesequential sheet S in a sheet shape along a cutting position which isset to have a predetermined length. In addition, on the furtherdownstream side of the sheet S in the transfer direction than the firstcutting unit 90 a, the second cutting unit 90 b is disposed to cut thesheet S along the transfer direction of the sheet S. The second cuttingunit 90 b is provided with a cutter, and cuts out (cuts) the sheet Salong a predetermined cutting position in the transfer direction of thesheet S. Accordingly, the sheet S having a desired size is formed. Thecut sheet S is loaded on a stacker 95 or the like after marking isperformed one by one by the marking unit 100.

1.5.11. Marking Unit

In the sheet manufacturing apparatus 120 of the embodiment, the markingunit 100 is disposed on the further downstream side than the sheetforming unit 40. The marking unit 100 can perform marking fordistinguishing the history of the sheet S, with respect to the sheet S.When manufacturing the sheet S, marking unit 100 may perform markingwhich has information that corresponds to the number of recycling of thesheet S into the raw material 1. The marking may be a mark with the samenumber as the number of recycling.

The marking unit 100 can perform marking on the sheet S which is cut bythe cutting unit 90 one by one. The position where the marking isperformed in the sheet S can be appropriately selected within a rangewhere the making is recognized by the obtaining unit 8.

Regarding a state of marking in the sheet S, if the state can bedetected in the obtaining unit 8, the appropriately known state ofmarking can be employed. When the obtaining unit 8 is an optical readingdevice, the marking unit 100 can employ a method of (1) opening a finehole on the sheet S, (2) performing printing by the ink which cannot beread by the eyes of a human, (3) performing embossing processing with aslight unevenness on the sheet S, and (4) printing a bar code which canput in multiple pieces of information.

In addition, as described above, as the information regarding thehistory of the raw material 1, which is included in the marking, it ispossible to include the number of recycles, a compound amount of theadditive agent, or a compound amount of additional fibers.

When the sheet S on which marking is performed is recycled as the rawmaterial 1 in this manner, the history may be obtained by reading themarking by the obtaining unit 8, and the control unit 110 may controlthe feed amount of the additive agent in the addition unit 32 inaccordance with the obtained history. In this manner, by using themarking, it is possible to understand the history of the raw material 1,such as the number of recycling.

1.5.12. Control Unit

Based on the information regarding the history of the raw material 1,which is output from the obtaining unit 8, the control unit 110 changesthe condition of the addition unit 32. Specifically, when theinformation regarding the history of the raw material 1, which is outputfrom the obtaining unit 8, for example, the number of recycles, is 0,the control unit 110 can set the amount of the additive agent to beadded in the addition unit 32 to a first amount which is necessary formanufacturing the sheet S. In addition, when the number of recycles is1, the control unit 110 can set the amount of the additive agent to asecond amount which is smaller than the first amount. In addition, basedon the information regarding the history of the raw material 1, thecontrol unit 110 does not change the amount of the additive agentimmediately. The amount of the additive agent is changed after the timefor performing processing and transferring the raw material 1 of whichthe history is obtained up to a place where the additive agent is addedelapses.

In addition, based on the information regarding the history of the rawmaterial 1, which is obtained from the obtaining unit 8, the controlunit 110 may select the type of the raw material 1 which is suppliedfrom the supplying unit 9. Specifically, when the plurality of types ofraw materials 1 is stored in the supplying unit 9, it is possible toselect the raw material 1 which is within a range where manufacturing ispossible with the same or the same level of feed amount of the additiveagent, and to supply the raw material 1 to the crushing unit 10.

Furthermore, based on the information regarding the history of the rawmaterial 1, which is obtained from the obtaining unit 8, the controlunit 110 may change the condition of the marking unit 100. Specifically,when the information regarding the history of the raw material 1, whichis obtained from the obtaining unit 8, is the number of recycles, it ispossible to send the command to the marking unit 100 to perform markingwhich corresponds to the number which is added by 1 to the number ofrecycles.

In addition, the control unit 110 can perform the control of each unitin the sheet manufacturing apparatus 120 from the obtaining unit 8 whichis at an upstream end up to the marking unit 100 which is at adownstream end.

For example, the control unit 110 is configured of a main control unitor a motor driving unit, an operation panel (operating unit), or aprocessing unit. A display unit displays each condition (for example,pressure of the pressing unit 60, or the like) that is selected by theuser. The operating unit is a unit for inputting the operation or thelike of the user as data. The operating unit is realized by hardware,such as a key board or a touch panel. The processing unit performsvarious types of processing, based on operation data from the operatingunit or a program. The processing unit is realized, for example, byvarious processors (CPU, DSP, or the like), hardware, such as ASIC (gatearray or the like), an application program, or an OS (for example, ageneral-purpose OS).

1.5.13. Others

In addition, although not illustrated in the drawing, downstream of theheating unit 50, a cooling unit which cools the sheet S heated by theheating unit 50 may be provided. The cooling unit can be configured of acooling roller or the like. By providing the cooling unit, it ispossible to rapidly cool the resin, and to solidify the structure of thesheet S in an early stage. Accordingly, for example, it is possible tocontribute to improving the throughput of the apparatus and to makingthe size of the apparatus small.

As the sheet manufacturing apparatus 120 of the embodiment can have aconfiguration other than the above-described configurations, and toappropriately have a plurality of configurations including theabove-described configuration in accordance with a purpose. The numberof order of each configuration is not particularly limited, and it ispossible to appropriately design the configurations in accordance withthe purpose.

The history of the raw material may be input by the user. In addition,the sheet manufacturing apparatus 120 of the embodiment is an apparatuswhich manufactures the sheet S by the dry method, but is not limitedthereto, and may be a manufacturing apparatus by the wet method.

2. Sheet Manufacturing Method

A sheet manufacturing method of the embodiment is a manufacturing methodof the sheet S by defibrating the raw material 1 including at least thefibers, adding the additive agent to the defibrated material, andbonding the plurality of fibers to each other via the additive agent.According to the history of the raw material 1, the feed amount of theadditive agent with respect to the raw material 1 varies.

The sheet manufacturing method of the embodiment can be performed byusing the above-described sheet manufacturing apparatus 120. Since theraw material, the defibration, the defibrated material, the fibers,mixing, the additive agent, the resin, the fibers, the sheet forming, orthe like are similar to those described in the above-described sectionsof the sheet manufacturing apparatus, the detail description thereofwill be omitted.

According to the sheet manufacturing method, by varying the amount ofthe additive agent according to the history of the raw material 1, it ispossible for the additive agent in the sheet S to be set to be of adesired amount. For example, when the sheet S has been recycled twice,the amount of the additive agent included in the defibrated materialvaries every time recycling is performed. However, by doing so, it ispossible for the amount of the additive agent in the manufactured sheetS to be set to be of a desired amount.

3. Other Items

In the specification, an expression “uniform” indicates that, in a caseof uniform scattering or mixing, in an object which defines two or moretypes or two or more phases of components, a relative position where onecomponent exists with respect to other components is similar in theentire system, or the positions are the same or substantially equivalentto each other in each part of the system. In addition, uniformity ofcoloring or uniformity of the color tone indicates that there is nolight and shade of the light when the sheet is viewed in a plan view,and a tone density is similar. However, even when the tone density issimilar, there is a case where the distances between all of the resinsare not the same, and the tone density is not completely the same aseach other.

In the specification, terms which mean the equivalence of the density,the distance, or the dimension, such as “uniform”, “the same”, or“equivalent interval”, are used. It is preferable that the density, thedistance, or the dimension is equivalent, but since it is difficult tobe completely equivalent, these terms also include a meaning that thevalues are not equivalent and shifted by an accumulation of errors orirregularities.

The invention is not limited to the above-described embodiment, andfurther, it is possible to have various modifications. For example, theinvention includes substantially the same configuration (a configurationin which the functions, the methods, and the result are the same, or aconfiguration in which the purpose and the effect are the same) as thedescribed configuration in the embodiment. In addition, the inventionincludes a configuration in which a part which is not essential in theconfiguration described in the embodiment is switched. In addition, theinvention includes a configuration in which the same operation effect asthat of the configuration described in the embodiment is achieved, or aconfiguration in which the same purpose can be achieved. In addition,the invention includes a configuration in which a known technology isadded to the configuration described in the embodiment. For example, theweb W is a single layer in the above-described embodiment, but may beplural layers, and may be a layer in which additionally creatednon-woven fabric or paper sheet is stacked.

4. Example

Hereinafter, by illustrating Examples, the invention will be describedin more detail. In addition, the invention is not limited to theExamples described below.

In Examples 1 and 2 described below, by using the sheet manufacturingapparatus (for example, the sheet manufacturing apparatus 120 providedwith the resin feeding unit 32 a and the fiber feeding unit 32 billustrated in FIG. 2) according to the invention, a regenerated papersheet for business is manufactured as the sheet S. FIG. 4 is a tableillustrating the additive agent or the like and a regenerated materialin each Example.

4.1. Manufacturing Raw Material

First, the raw material which is used in Example 1 is manufactured.Here, as illustrated in FIGS. 2 and 4, the printed waste paper sheet(waste paper which is printed) of the copy paper sheet for businessmanufactured by the wet method, is supplied from the supplying unit 9 asan initial raw material. Since the printed waste paper sheet does nothave the history of the raw material, the number of recycling as the rawmaterial is 0. By using the shredder as the crushing unit 10, the rawmaterial (printed waste paper sheet) supplied from the supplying unit 9is cut out into small pieces having approximately 6 mm×14 mm.

By using the defibrating machine as the defibrating unit 20, the rawmaterial which is cut out in the crushing unit 10 is defibrated. Therotational speed (rotational speed of the rotary unit of the defibratingunit 20) of the defibrating unit 20 is 5000 rpm.

By using the cyclone as the classifying unit 63, the defibrated materialwhich passes through the defibrating unit 20 is classified.

By using the rotary sieve as the screening unit 35, the classifiedmaterial which passes through the classifying unit 63 is screened by thelength of the fibers. As the net of the screening unit 35, a net having970 μm in aperture is used.

In the mixing unit 30, with respect to 100 parts by weight of thedefibrated material (fibers) which passes through the screening unit 35,15 parts by weight of the resin powder which are supplied from the resinfeeding unit 32 a of the addition unit are mixed in. In the mixing unit30, by using a turbo fan blower, the defibrated material and the resinare mixed in the air. The screw feeder is used as the resin feeding unit32 a. The resin powder having the average grain size D50=10 μm which ismade by integrating titanium oxide with polyester resin, is used.

By using the rotary sieve as a refining unit 70, the mixture which ismixed in the mixing unit 30 is refined. As the net of the refining unit70, the net having 970 μm in aperture is used.

While operating the suction mechanism 78 of the deposition unit 75, andmoving the mesh belt 76, the defibrated material which passes throughthe refining unit 70 is deposited on the mesh belt 76. After this, theweb W which is deposited on the mesh belt 76 is carried to the pressingunit 60.

The web W is pressed by the appropriate pressing force by the pressingroller 61 in the pressing unit 60, and is heated to the temperaturewhich is equal to or greater than the temperature at which the resin inthe additive agent is melted by two pairs of the heating rollers 51 inthe heating unit 50.

Furthermore, the web W is cut out to have the A4 size in the cuttingunit 90. After this, the information which corresponds to the number ofrecycles 1 is given the marking by the marking unit 100.

By the above-described process, as the raw material which is used inExample 1, the copy paper sheet for business which is the regeneratedmaterial is manufactured.

4.2. Example 1

In Example 1, as illustrated in FIG. 4, by using the copy paper sheetfor business which is manufactured in the above-described 4.1 as the rawmaterial, similarly, the copy paper sheet for business is manufactured.In this case, the number of recycling of the raw material is 1. Withrespect to 100 parts by weight of the defibrated material (fibers), theamount of the resin powder which is added to the defibrated material inthe resin feeding unit 32 a is 10 parts by weight, and the informationwhich corresponds to the number of recycles 2 is given the marking bythe marking unit 100. Except these, the process is similar to themanufacturing process of the above-described 4.1.

A part of the resin which is added in the above-described 4.1 is notcompletely removed by the defibrating unit 20 and the classifying unit63, and is adhered to the fibers of the defibrated material which isclassified by the classifying unit 63. However, as the amount of theresin powder is 10 parts by weight which is less than that in theabove-described 4.1 by 5 parts by weight, in Example 1, the copy papersheet for business which has the same function as that of the papersheet manufactured in the above-described 4.1 can be manufactured.

4.3. Example 2

In Example 2, as illustrated in FIG. 4, by using the copy paper sheetfor business which is manufactured in Example 1 as the raw material,similarly, the copy paper sheet for business is manufactured. In thiscase, the number of recycling of the raw material is 2. With respect to95 parts by weight of the defibrated material (fibers), the amount ofthe resin powder which is added to the defibrated material in the resinfeeding unit 32 a is 10 parts by weight, and 5 parts by weight of fibersis fed from the fiber feeding unit 32 b. Except these, the process issimilar to the manufacturing process of the above-described 4.1. Byfeeding 5 parts by weight of fibers from the fiber feeding unit 32 bwith respect to 95 parts by weight of the defibrated material (fibers),the total is 100 parts by weight of fibers.

The fibers which are fed from the fiber feeding unit 32 b uses the samedefibrated material as the defibrated material which passes through thescreening unit 35 in the above-described 4.1.

Since a part of the resin is adhered to the fibers of the defibratedmaterial which is classified by the classifying unit 63, by the samelevel of amount as that of the fibers used in Example 1, in Example 2,the amount of the resin powder is 10 parts by weight which is the sameas in Example 1. In addition, since the fiber of the defibrated materialwhich is classified by the classifying unit 63 are mixed with the fiberswhich deteriorate and have a short fiber length, in Example 2, byreducing the amount of the defibrated material to 95 parts by weight andadding 5 parts by weight of fibers, the copy paper sheet for businesswhich has the same function as that of the paper sheet manufactured inthe above-described 4.1 can be manufactured.

An advantage of some aspects of the embodiment is to provide a sheetmanufacturing apparatus and a sheet manufacturing method, in which it ispossible to manufacture a sheet including a desired amount of anadditive agent which is in the sheet that has been recycled pluraltimes.

The embodiment can be realized in the following forms or applicationexamples.

(1) According to an aspect of the embodiment, there is provided a sheetmanufacturing apparatus, including: a defibrating unit which defibratesa raw material including at least fibers; an addition unit which adds anadditive agent to a defibrated material which is defibrated in thedefibrating unit; and a sheet forming unit which forms a sheet bybonding a plurality of fibers to each other via the additive agent.According to a history of the raw material, an amount of the additiveagent which is fed by the addition unit varies.

In this case, depending on the amount of the additive agent which variesaccording to the history of the raw material, it is possible for theadditive agent in the sheet to be set to be of a desired amount.

(2) In the sheet manufacturing apparatus according to the aspect of theembodiment, the history may be information which corresponds to thenumber of recycling of the raw material in the past.

In this case, as the amount of the additive agent varies according tothe information which corresponds to the number of recycling of the rawmaterial into sheets, even when the amount of the additive agentincluded in the raw material due to recycling changes, it is possible toset the amount of the additive agent included in the sheet to bemanufactured to a desired amount. For example, when the raw material hasbeen recycled twice, the amount of the additive agent included in thedefibrated material varies according to the number of times ofrecycling, but in this manner, it is possible for the additive agent inthe sheet to be set to be of a desired amount.

(3) In the sheet manufacturing apparatus according to the aspect of theembodiment, the amount of the additive agent to be fed may be decreasedwhen the number of times a raw material has been recycled is largerrelative to when the number of times a raw material has been recycled isfewer.

In this case, since a raw material which has been recycled a largenumber of times tends to include a large amount of the additive agent,by decreasing the amount of the additive agent to be fed, there being anexcessive amount of additive agent in the sheet is prevented.

(4) The sheet manufacturing apparatus according to the aspect of theembodiment, may further include a fiber feeding unit which feeds morefibers into the defibrated material which is defibrated in thedefibrating unit. An amount of the fibers fed by the fiber feeding unitmay be increased when the number of times a raw material has beenrecycled is larger relative to when the number of times a raw materialhas been recycled is fewer.

In this case, since a proportion of short fibers included in the rawmaterial which has a larger number of recycling tends to be higher, itis possible to reduce the proportion of short fibers by feedingadditional fibers.

(5) The sheet manufacturing apparatus according to the aspect of theembodiment, may further include: a marking unit which performs markingfor displaying the information which corresponds to the number ofrecycling when the sheet is manufactured; an obtaining unit which readsthe marking and obtains the history; and a control unit which controlsthe feed amount of the additive agent in accordance with the obtainedhistory.

In this case, it is possible to ascertain information regarding thehistory of the raw material, which corresponds to the number ofrecycling by using the marking.

(6) According to another aspect of the embodiment, there is provided asheet manufacturing method, including: defibrating a raw material whichincludes at least fibers; adding an additive agent to a defibratedmaterial; and bonding a plurality of fibers to each other via theadditive agent. According to a history of the raw material, a feedamount of the additive agent with respect to the raw material varies.

In this case, depending on the amount of the additive agent variesaccording to the history of the raw material, it is possible for theadditive agent in the sheet to be set to be of a desired amount. Forexample, when the raw material has been recycled twice, the amount ofthe additive agent included in the defibrated material varies every timerecycling is performed, but in this manner, it is possible for theadditive agent in the manufactured sheet to be set to be of a desiredamount.

(7) According to still another aspect of the embodiment, there isprovided a sheet manufacturing apparatus, including: a defibrating unitwhich defibrates a raw material including at least fibers; an additionunit which adds an additive agent to a defibrated material which isdefibrated in the defibrating unit; a sheet forming unit which forms asheet by bonding a plurality of fibers to each other via the additiveagent; an obtaining unit which obtains history of the raw material; anda control unit which changes a feed amount of the additive agent inaccordance with the obtained history.

In this case, since it is possible to change the amount of the additiveagent in accordance with the history of the raw material by the controlunit, it is possible for the additive agent in the sheet to be set to beof a desired amount.

What is claimed is:
 1. A recycled sheet in which fibers are bonded viaan additive agent, the recycled sheet comprising: a history includinginformation that is related to characteristics.
 2. The recycled sheetaccording to claim 1, wherein the history includes the information thatis related to at least one of a content of the additive agent, a type ofthe additive agent, a length of the fibers, a material of the fibers,information on the number of times of being recycled, informationcorresponding to a type of the recycled sheet, and information on asheet manufacturing apparatus that is used in recycling.
 3. The recycledsheet according to claim 1, wherein the history is represented by atleast one of a character, a symbol, a hole, an unevenness, and a barcode.
 4. The recycled sheet according to claim 1, wherein the additiveagent is a complex body in which resin and coagulation inhibitor areintegrated.
 5. The recycled sheet according to claim 1, wherein theadditive agent is a complex body in which resin and coloring materialare integrated.
 6. The recycled sheet according to claim 1, wherein theadditive agent is a complex body in which resin, coagulation inhibitor,and coloring material are integrated.